Statistical Analysis on Threshold of Haemoglobin A1C (HBA1c) for Diabetes Diagnosis and the Relationship Between HBA1c and Plasma Glucose Concentrations in Chinese Diabetic High-Risk Groups.

BACKGROUND: The goal is to evaluate the threshold of hemoglobin A1C (HBA1c) for screening test among Chinese patients with diabetes and high-risk groups in the endocrinological department and identify the relationship between HbA1c and plasma glucose. METHODS: Experimental design: This study is based on the data selected from patients without clinical intervention enrolled in the Endocrinology Department and Admission Office in our hospital. It uses the four-point plasma glucose modeling and trapezoidal integration method to analyze the relationship between HbA1c and each plasma glucose threshold in an oral glucose tolerance test (OGTT). SETTING: Harbin, China, from January 1st of 2010 to December 31st of 2012. PARTICIPANTS: 2,853 16 - 85 year-old patients who came to our Endocrinology Department to take venous blood measurements and OGTT. SELECTION CRITERIA: The OGTT and HbA1c were performed simultaneously, unless acidosis was present, without considering past history of diabetes and oral hypoglycemic drugs or insulin treatment, or other basic combined diseases. Pregnant patients were excluded. RESULTS: The area under the receiver operating characteristics curve (ROC) was 0.902 (95% confidence interval 0.890 to 0.914) for HbA1c alone and 0.915 (0.906 to 0.925) for fasting plasma glucose (FPG) alone. The HbA1c threshold of 6.5% showed the highest Youden index of 64.4%, and significantly higher sensitivity (81.1%, 79.3% to 82.7%) than FPG ≥ 7.0 mmol/L (69.8%, 67.8% to 71.8%) (p < 0.0001) and higher specificity (83.3%, 80.4% to 85.8%) than HbA1c ≥ 6.3% (76.3%, 73.2% to 79.3%) (p < 0.0001) in detecting diabetes, together with a low negative likelihood ratio of 0.2. In addition, the threshold of 1/2 hour postprandial glucose and that of 1 hour postprandial glucose are 10.6 mmol/L and 13.6 mmol/L, respectively. Thus, the relative contribution of FPG increased gradually with increasing levels of HbA1c: 15.9% in the lowest vs. 44.0% in the highest quintile (p < 0.001). The relative contribution of 1-hour postprandial glucose decreased progressively from the lowest (25.0%) to the highest quintile of HbA1c (14.2%, p < 0.001). CONCLUSIONS: These findings suggest that the optimal HbA1c threshold of 6.5% as a screening criterion for diabetes and high-risk groups may be acceptable. This paper is trying to put forward the thresholds of 1/2-hour plasma glucose and 1-hour plasma glucose for diagnosing diabetes. The relative contribution of FPG increased gradually with increasing levels of HbA1c; however, the contribution of postprandial glucose decreased progressively.

Optimal cut-off points of fasting plasma glucose for two-step strategy in estimating prevalence and screening undiagnosed diabetes and pre-diabetes in Harbin, China.

To identify optimal cut-off points of fasting plasma glucose (FPG) for two-step strategy in screening abnormal glucose metabolism and estimating prevalence in general Chinese population. A population-based cross-sectional study was conducted on 7913 people aged 20 to 74 years in Harbin. Diabetes and pre-diabetes were determined by fasting and 2 hour post-load glucose from the oral glucose tolerance test in all participants. Screening potential of FPG, cost per case identified by two-step strategy, and optimal FPG cut-off points were described. The prevalence of diabetes was 12.7%, of which 65.2% was undiagnosed. Twelve percent or 9.0% of participants were diagnosed with pre-diabetes using 2003 ADA criteria or 1999 WHO criteria, respectively. The optimal FPG cut-off points for two-step strategy were 5.6 mmol/l for previously undiagnosed diabetes (area under the receiver-operating characteristic curve of FPG 0.93; sensitivity 82.0%; cost per case identified by two-step strategy ¥261), 5.3 mmol/l for both diabetes and pre-diabetes or pre-diabetes alone using 2003 ADA criteria (0.89 or 0.85; 72.4% or 62.9%; ¥110 or ¥258), 5.0 mmol/l for pre-diabetes using 1999 WHO criteria (0.78; 66.8%; ¥399), and 4.9 mmol/l for IGT alone (0.74; 62.2%; ¥502). Using the two-step strategy, the underestimates of prevalence reduced to nearly 38% for pre-diabetes or 18.7% for undiagnosed diabetes, respectively. Approximately a quarter of the general population in Harbin was in hyperglycemic condition. Using optimal FPG cut-off points for two-step strategy in Chinese population may be more effective and less costly for reducing the missed diagnosis of hyperglycemic condition.

Body mass index and susceptibility to knee osteoarthritis: a systematic review and meta-analysis.

OBJECTIVE: Excess bodyweight, expressed as increased body mass index, is associated with osteoarthritis risk, especially in weight bearing joints. However, the strength of the association was inconsistent. The study was conducted to quantitatively assess the association between body mass index and the risk of knee osteoarthritis and investigate the difference of the strength stratified by sex, study type and osteoarthritis definition. METHODS: We used published guidelines of the Meta-analysis of Observational Studies in Epidemiology Group (MOOSE) to perform the meta-analysis. The search strategy employed included computerized bibliographic searches of MEDLINE, PubMed, EMBASE, The Cochran Library and references of published manuscripts. Study-specific incremental estimates were standardized to determine the risk of knee osteoarthritis associated with a 5 kg/m(2) increase in BMI. RESULTS: Twenty-one studies were included in the study. The results showed that body mass index was significantly positive associated with osteoarthritis risk in knee site. A 5-unit increase in body mass index was associated with an 35% increased risk of knee osteoarthritis (RR: 1.35; 95%CI: 1.21, 1.51). Magnitude of the association was significantly stronger in women than that in men with significant difference (men, RR: 1.22; 95%CI: 1.19, 1.25; women, RR: 1.38; 95%CI: 1.23, 1.54; p=0.04). The summary effect size was 1.25(95%CI: 1.18, 1.32) in case-control studies and 1.37 (95%CI: 1.19, 1.56) in cohort studies (p=0.28). Body mass index was positively associated with knee osteoarthritis defined by radiography and/or clinical symptom (RR: 1.25, 95%CI: 1.17, 1.35) and clinical surgery (RR: 1.54, 95%CI: 1.29, 1.83). The latter tended to be stronger than the former (p<0.01). CONCLUSION: Increased body mass index contribute to a substantially increased risk of knee OA. The magnitude of the association varies by sex and OA definition.

The relationship between body mass index and hip osteoarthritis: a systematic review and meta-analysis.

OBJECTIVE: Body mass index, a measure of relative weight, is increasingly recognized as an important risk factor for osteoarthritis, especially in weight bearing joints. The objective was to assess the association between body mass index and hip osteoarthritis susceptibility and investigate the difference between sex, study type and osteoarthritis definition. METHODS: We did electronic searches of Medline, Embase and Cochrane library from the commencement to December 2009. A meta-analysis and meta-regression was executed to quantitatively assess the strength of associations between body mass index and hip osteoarthritis risk. Study-specific incremental estimates were standardized to determine the risk associated with a 5 kg/m(2) increase in body mass index. RESULTS: Fourteen epidemiological studies were included. Our study showed that body mass index was significantly positive associated with hip osteoarthritis risk. A 5-unit increase in body mass index was related to an increased risk of hip osteoarthritis (RR: 1.11; 95%CI: 1.07, 1.16). The magnitudes of associations were similar in women as compared with men (women, RR: 1.10; 95%CI: 1.05, 1.15; men, RR: 1.08; 95%CI: 1.04, 1.12; p > 0.05). The summary estimates were 1.12 (95%CI: 1.02, 1.24) in case-control studies and 1.11 (95%CI: 1.06, 1.16) in cohort studies (p > 0.05). Body mass index was positively associated with hip osteoarthritis defined by radiography and/or clinical symptom (RR: 1.04; 95%CI: 1.00, 1.07) and clinical surgery (RR: 1.16; 95%CI: 1.11, 1.22) with no significant difference (p > 0.05). CONCLUSION: Increased body mass index contributes to a positive effect on susceptibility to hip osteoarthritis. Associations between body mass index and hip osteoarthritis risk do not vary by sex, study design or osteoarthritis definition.